Conventional tank-mounted automotive fuel pumps typically have a rotary pumping element encased within a pump housing. Fuel flows into a pumping chamber within the pump housing and the rotary pumping action of the vanes and the vane grooves of the rotary pumping element cause the fuel to exit the housing at a higher pressure. Regenerative turbine fuel pumps are commonly used to pump fuel to automotive engines because they have a higher and more constant discharge pressure than, for example, positive displacement pumps. In addition, regenerative turbine pumps typically cost less and generate less audible noise during operation. A problem may develop, however, when the pump pumps high temperature fuel at a high flow rate. When high temperature fuel (140.degree. F.-160.degree. F.) is pumped at high velocity (which is required at high engine demand), cavitation may occur, which in turn, causes pump flow to drop by as much as 40%. Thus, a single stage pump may be unable to meet high engine demand by preventing cavitation. Prior art devices overcome this problem by utilizing an expensive two-stage pump. The present invention, on the other hand, overcomes this problem utilizing a low cost, single-stage pump having a unique inlet port and channel configuration that improves the net positive suction head (NPSH) and hot fuel handling capability by reducing inlet flow losses and cavitation, both of which would otherwise cause fuel vaporization and audible noise.
Accordingly, an advantage of the present invention is that hot fuel handling is improved by reducing inlet flow losses and cavitation.
Another advantage of the present invention is that a low cost, single stage pump can be used to pump high temperature fuel at high velocity.
Still another advantage of the present invention is that fuel vaporization and audible noise is reduced.